Inkjet printers typically have a printhead mounted on a carriage that scans back and forth across the width of a sheet of paper feeding through the printer. Ink from an ink reservoir, either on-board the carriage or external to the carriage, is fed to ink ejection chambers on the printhead. Each ink ejection chamber contains an ink ejection element, such as a heater resistor or a piezoelectric element, which is independently addressable. Energizing an ink ejection element causes a droplet of ink to be ejected through a nozzle for creating a small dot on the medium. The pattern of dots created forms an image or text.
As dot resolutions (dots per inch) increase along with the firing frequencies, more heat is generated by the firing elements. This heat needs to be dissipated. Heat is dissipated by a combination of the ink being ejected and the printhead substrate sinking heat from the ink ejection elements. The substrate may even be cooled by the supply of ink flowing to the printhead.
Additional information regarding one particular type of printhead and inkjet printer is found in U.S. Pat. No. 5,648,806, entitled, "Stable Substrate Structure For A Wide Swath Nozzle Array In A High Resolution Inkjet Printer," by Steven Steinfield et al., assigned to the present assignee and incorporated herein by reference.
As the resolutions and printing speeds of printheads increase to meet the demanding needs of the consumer market, new printhead manufacturing techniques and structures are required. Hence, there is a need for an improved printhead that has at least the following properties: adequately sinks heat from the ink ejection elements at high operating frequencies; provides an adequate refill speed of the ink ejection chambers with minimum blowback; minimizes cross-talk between nearby ink ejection chambers; is tolerant to particles within the ink; provides a high printing resolution; enables precise alignment of the nozzles and ink ejection chambers; provides a precise and predictable drop trajectory; is relatively easy and inexpensive to manufacture; and is reliable.